1. Technical Field
The present disclosure relates to a pixel driving circuit and a display device having the same, and more particularly, to a pixel driving circuit and a display device having the same, with a varying scan direction.
2. Discussion of Related Art
Display devices can display an image by providing image signals to a plurality of pixels. A liquid crystal display (LCD) device displays a desired image by changing the light transmittance of liquid crystal for each pixel. Such a display device includes: a display panel having a plurality of pixels; and gate/data drivers controlling the operations of the pixels. The gate driver provides a gate turn-on voltage (e.g., a scan signal) sequentially to a plurality of gate lines connected to the pixels. The data driver provides a data signal to a plurality of data lines connected to the pixels. Thus, the pixels receiving the gate turn-on voltage are enabled, and the data signal is provided to the enabled pixels to display a desired image.
In a conventional design, a gate driver is fabricated in an IC configuration and the fabricated gate driver is mounted on a display panel. However, a sufficient mounting space is needed to mount the gate driver. Another conventional design integrates the gate driver into the display panel to reduce the size of the display panel. The gate driver is fabricated simultaneously with the pixel elements. The gate driver includes a plurality of stage units corresponding respectively to a plurality of gate lines. In order to provide a gate turn-on voltage to the gate lines sequentially through the stage units, each of the stage units uses an output signal of a previous stage unit as an enable signal.
It is desirable to be able to display smooth images even when a display panel is rotated freely. When a gate turn-on voltage is provided to gate lines sequentially through stage units, the applying direction of the gate turn-on voltage is changed by rotation of a display panel. For example, when the display panel is rotated by 180°, the direction of the gate turn-on voltage, which was provided sequentially from top to bottom of the non-rotated display panel, is inverted. The direction is inverted because each of the stage units is enabled by the next stage unit due to the 180° rotation of the display panel. A gate turn-on voltage may be applied to provide a signal corresponding to a desired gradation of a pixel and then a separate boosting voltage can be provided to change the gradation of the pixel. However, when the display panel is then rotated by 180°, the boosting voltage is provided before application of the gate turn-on voltage, thus losing the benefit of the boosting voltage.